Launching, suspending, and resuming apps

When users move your app off-screen, Windows 8 suspends your app in memory. This allows another app to have the foreground. When an app is suspended, it is resident in memory, and Windows has stopped it from running.

When users bring your app back to the foreground, they expect the app to resume where they left off. As long as your app stays suspended, Windows automatically preserves your app's data in memory and restores it when your app resumes.
Apps are also terminated occasionally, so your app should use suspending events to save its current state.

Note If you need to do asynchronous work when your app is being suspended you will need to defer completion of suspend until after your work completes. You can use the GetDeferral method on the SuspendingOperation object (available via the event args) to delay completion of suspend until after you call the Complete method on the returned SuspendingDeferral object.

Background file transfer

Background tasks

You can use background tasks to run lightweight code in the background. Any app can register a background task in response to certain system events. Background tasks can't run code that directly updates the UI; instead, they show information to the user with tile updates, badge updates, and toast notifications. Some apps, like mail, VOIP, and IM, allow the user to communicate in real-time. If the user allows, your app can show a badge or tile on the lock screen. When your app is on the lock screen, it gains access to real-time background tasks.

Kid's Corner

Kid’s Corner is a Windows Phone feature that allows the user to put their phone in a special mode for kids, in which only the apps and media they specify can be accessed. An app can detect at run time if it is running in Kid’s Corner mode and modify its behavior and UI to be appropriate for a child user. See Detecting when your app is running in Kid's Corner mode.